SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8497190bffbd80d70290790022d33168c0f0ce9ea4920479efb44249d098cb0f' 
  AND token = '/i25r8CXDyFD6hVHVS5UaWdkzlgV7ew2hFWPY5zGTWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}